Process of making a contact transfer printing surface with a colored emulsion



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To all whom it may concern:

Be it lrnown that if, Runner Jenn, a cit izen of the United States, residing at New York, in the county of New Yorlr and State of New York, have invented certain new and useful Processes of Making a "Contact Transfer Printing Surface with a @olored Emulsion, of which the following is a specification.

ll ly invention relates to a process of mahing a contact transfer rinting surface with a colored emulsion and has for its object to produce a printing surface which is mounted on a suitable carrier and which represents photographic lights and shades in such a manner that copies may be made therefrom by a dye or inlr transfer contact process. [in illustrative dye contact transfer prcess is disclosed in patent to Shljpherd and art lett, No, 728,310, granted ay 19, 1903, for photographic printing, and an illustrative inlr contact transfer process is disclosed in tlassells Gyclopeedia of Photography, Cassell a Co, New York, 1912, at page 1%.- under the title Collot pe, it being understood, however, that t e processes thus il lustrated do not disclose a printing plate having the novel and beneficial characteristics of the printing plate obtained by the process disclosed and claimed herein. More specifically, my invention relates to the for-' mation of a printing surface obtained by eaposing to the action of light modified by the lights and shades which it is desired to reproduce, a sensitized emulsion mounted on a transparent carrier through which it preferably is exposed, which then is treated to form a hardened printing sur face consisting of granules or great numbers of photographically formed, extremely nuinute, individual. protuberances which are distributed and grouped irregularly so as to represent photographic lights and shades. 'lfhe exposure light may be of any hind, such for example, as a reflected light as in a camera, or a transmitted light as in printing from a negative.

in the embodiment of my invention chosen for purposes of illustration, the printing surface referred to may be obtained by the process described in my Patent lilo. 1,37l,853, granted April 12, 1921, for process of photographic reproduction.

Application died dctoher at, rate. tierlal its. states.

in accordance with that process, the ex posed emulsion may be treated by a developing solution containing a hardening or tanning agent which renders insoluble or unremovable the emulsion adjacent its light affected, light sensitive content, the effect of which agent is controlled or limited selectively by the presence of varying quantitles of a neutralizing agent, after which the soluble or removable portions of emul S1011 are removed in any desired manner, as, for example, by melting with warm water.

A sample formula for a developing sol'u tion containing a hardening or tannin agent the eflect of which is controlled and limited selectively by the resence of vary ing quantities of a neutra'izing agent is as follows:

Water .4 8.5 ounces Pvrogallic acid ll grains (ll etol .9 grains Potassium bromide at grains Sodium carbonate "200 grains Sodium sulphite "id to '80 grains in the above sample formula the harden mg or tanning agent is pyrogallic acid, and the controlling and limiting agent is sodium sulphite which may be varied in amount so lectively within limits to obtain the desired result, llt is well known that pyrogallic acid also is a developing agent and that sodium sulphite is a preservative adapted to prevent oxidation of the pyrogallic acid in solution. @ther hardening and tanning agents and other neutralizing agents may be used, the above formula representing one developing solution by which the process may be carried out. Potassium bromide, for exam is, also has a certain controlling and limiting effect. The main difference be tween the above sample formula and stand ard developing formulas is in the amount of sodium sulphite used. lln standard formulas the amount of sodium sulphite used is so greatly in excess of the amount used in the above sample formula that the tanning or hardening efiect of the pyrogallic acid is en tirely neutralized or overcome. lln the sample formula, the sodium sulphite merely controls and limits the hardening effect of the pyrogallol, ft is of course understood by tltl tltli ltl ill

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ltlll lilld those skilled in the art that when a thick layer of emulsion is treated, or when the exposure is through the transparent carrier, it is advisable, in order to accelerate the action of the pyrogallic acid, to use larger quantities of an accelerator such, for example, as sodium carbon-ate or its equivalents than when the emulsion layer is thin or exposed on its face. When larger quantitles of sodium carbonate thus are used, it is necessary to increase the amount of sodium sulphite. The above sample formula is for treatment of an emulsion exposed through its transparent carrier and therefore contains a comparatively large amount of sodium carbonate with an increased amount of sodium sulphite. In order to obtain the desired printing surface, however, the amount of sodium sulphite in the process disclosed herein is much less than would be used in a developin solution for the usual development of t e particular emulsion layer to be treated. Although it is referable for reasons of convenience to embody the selectively controlled hardening agent in the developer solution, it may be used separately if desired, b such modification of the developer so ution as will prevent such a hardening of the emulsion as will prevent the selective hardenlng desired.

It is believed that the hardening or tanning effect of the pyrogallic acid exerts its action first adjacent the so-called latent image, or in other words, on the portions of emulsion adjacent the particles of silver salts affected b the exposure light and converted by the eveloper into metallic silver. Thus in a silver bromide film, the throwin off of the bromide from a light afiecte silver bromide particle in the developing process, probably acts or reacts with the pyrogallic acid to harden or tan or render insoluble or unremovable the adjacent emulsion. Thus in the embodiment chosen for purposes of illustration, the reaction products from the chemical effects of the developer solution, are believed *to act or react with the selectively controlled hardening agent. However this may be, it is necessary for purposes of my invention as disclosed in said Patent No. 1,374,853, dated April 12, 1921, only either to harden particles of emulsion adjacent light affected particles of the light sensitive content in any desired manner, or in reverse manner to leave unhardened the particles ofemulsion adjacent light affected particles of the light sensitive content and harden the remaining emulsion, the essential result being a hardened emulsion surface corresponding to the lights and shades to be reproduced which will acquire and give up any desired color in a comparatlvely short time. By' controlling the hardening or tanning effect of the pyrogallic acid as above set forth, only the articles of emulsion adjacent the said light affected particles of silver salts are hardened, the relative roportions of the hardening agent (whether or not accelerated b an accelerating agent) and of the neutra izing agent being such as to control selectively the effective area of influence of the hardening agent. The unhardened portions, as stated above, then may be removed in any desired manner as by lacing the emulsion in warm water whici causes the un hardened or soluble portions to soften and melt away from the hardened or insoluble portions so that the hardened emulsion alone will remain in the form of extremely minute, individual protuberances which are distributed and grouped irregularly so as to represent the photographic lights and shades which it is desired to reproduce.

It is considered desirable in producing a printing surface to expose the sensitlzed emulsion through its transparent carrier rather than on its outside surface in order that the printing surface may be as close as possible to the carrier. If the emulsion is exposed on its outside surface, it is necessary to strip the emulsion from its carrier in order to remove the unhardened portions which will lie adjacent the carrier. Stripping the emulsion is a delicate operation which can be performed only by those skilled in the art and is likely to injure the image.

When an emulsion is exposed through its transparent carrier, however, certain difiiculties are encountered in the formation of the printing surface, which preferably should be very thin and lie ad acent the transparent carrier. As an ordinary commercial sensitized emuldon usually is in excess of one-thousandth of an inch in thickness, it is evident that it is likel to be penetrated deeply byv the light to w ich it is exposed, particularly by the stronger or more intense portions thereof. The resultant printing surface after treatment will have a relativel too thick printing surface in those portions which have been thus deeply penetrated. It is very difficult, for example, to get the darker ortions of a negative recorded properly without having the lighter portions of a negative registered too heavy and deep.

In order to overcome these disadvantages, I have discovered that excellent results may be obtained by using an emulsion colored with a color which is complementary to the exposure light. When applied to photographic printing from a negative, for example, the color will be complementary to the printing light, which generally is obtained from an incandescent electric lamp giving out blue rays. Naphthol yellow or its color equivalents in an aqueous solution iii lit"

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intents oi suhsntielly ten tltll grnms oi nephthol yellow to en ounce oi liquid will give setisiectory results with such e light es well on runny other oi the orenge end yellow dyes.

lli en ordinery sensitised emulsion oi eny desired'thiclrness end colored es descrihed ehove is exposed to such e printing light modified hy eny desired lights end shedes es, ior instence, those oi e netive which it is desired to re reduce, the printing light which comes trou h the high lights oi the negetive will he e sorhed or slowed down to such en extent thet the printing light which comes through the derlr shedes oi the negetive will he recorded in the sensitised emulsion, without e too deep penetretion oi the printin light coming through seid high lights oi t e negetive. ii the sensitised emulsion is exposed through its trenspercnt cerrier, the entire printing suriece ohteined eiter treetment will lie odjecent the cerrier, which is desirehle to prevent e too'greet thichness oi printin suriece corresponding to the high lights '0 the negetive, the sect oi which excessive thickness is to ceuse the lihts end shedes to he too contresting.

tinny modiiicetions oi my invention will he epperent to those sliilled in the ert without deperting therefrom or irom the scope oi the cleims my invention not heing limited to eny perticuler emulsion or to eny perticuler light hut comprising the use oi en emulsion complementary in color the exposure light,

y the term metol in this cese is recent monomethylperemidophenol sulphate or its enuivelents.

het l cleim is:

l. The process oi forming e photogrephic record oi lights end shades cepehle oi use e trensfer printin plete, which comprises coloring e sensitized emulsion with e color complementnr to the exposure light exposing said emu sion to the lights end shedes desired to he recorded, end herdenin portions of emulsion adjacent the light oiliected sensitive content of e photographic emulsion with en egent adopted to harden seid emulsion hy reaction with the light eiiected sensitive content of the emulsion, and with e neutralizing agent for said herdening egent, the relative proportions oi seid herdening end neutralizing agents heing such we to control selectively the efiiective eree oi iniluence oi the herdening i cut hut to en extent less then the complete neutreli netion oi seid herdenin egent,

The process speci "red in cleim l in which the exposed sensitive emulsion is un developed prior to seid treetment.

3. The which the erdened portions correspond to the verietions oi the lights end shedes to which the sensitive emulsion hes heen esposed.

l. The process specified in cleim l in which the sensitive content is e silver suit.

5., The process specified in cleim l in which the herdening egent else is e developing egent.

ti. The process specified in cleim l in which the herdening egent is pyrollic ecid.

l. The process specified in cleim l in which the neutrelieing egent elso is or preservetive.

8. The process specified in cleim l in which the neutrelieing egent is sodium sulhite. p 9. The process specified in cleim l in which the herdening egent elso is e developing egent end in which the neutrelining egent elso is e preservetive,

10.. The process specified in cleim l in which the herdcning egent is pyrogellic ecid end the neutrelieing egent is sodium sulhite. p ll, The process specified in cleim l. in which the sensitive content is developed et the sums time the jecent the light eected sensitive emulsion ere herdened.

1%. The process specified in cleim l in which seid treetment is epplied to e photographic emulsion mounted on end exposed through e trensperent cerrier.

13. The process oi cleim l in which the color is nephthol yellow.

it. The recess oi cleim l in which the color is o teined irom suhstentielly ten grains oi nephthol yellow to en ounce oi li uid.

n testimony thet T cleim the iore oing, T have hereunto set my hund this fill dey oi recess specified in cleim l' in l ortions oi emulsion edtill till 

